


Unlike Any Other

by wafflete (cloustel)



Category: Undertale (Video Game)
Genre: Alternate Universe, Autism, Chemistry, F/M, Flirting, Gen, Gore, Madness, Murder, Pasta, Platonic Relationships, Smoking, Swapfell, Underfell, fellswap, underswap - Freeform
Language: English
Status: In-Progress
Published: 2018-11-23
Updated: 2018-11-23
Packaged: 2019-08-26 13:59:30
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings, Major Character Death
Chapters: 5
Words: 3,623
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16682947
Author URL: https://archiveofourown.org/users/cloustel/pseuds/wafflete
Summary: Sorry for the lack of detail or any actual science action! I'm not into science or am I qualified to say anything here is credible (/ω＼)





	1. Chapter 1

**[   H U M A N T A L E   ]**

 

Draining the water and turning the stove off, Papyrus, in his pink apron and chef hat, smiled. The sweet smell of sauce wafted through the entire house, and his dish seems ready to go and ready to eat.

He remembered to put the spices in, and a dash of salt, thanks to Frisk’s advice. Papyrus was sure he perfected it this time.

Walking over to the dish rack to get a plate, he returns to his pot, putting a generous amount of the noodles and pasta.

Papyrus was holding the platter now with a neat mound of spaghetti on it. The pasta looked heavenly, but no one was there to taste his new recipe. Sans was snoozing on the couch, and was out cold. Everyone else was doing whatever it is they were doing for the weekend. He sighed. “I GUESS I, THE GREAT PAPYRUS, WOULD HAVE TO EAT THIS MYSELF!”

It was sad that he was alone and had no one to share it with. It would have been nice if he actually had someone over to congratulate and compliment him for such a job well done.

Sighing, he took the fork and jabbed it into the small pile of pasta.

Just when he was about to try out his new recipe, there came a knock on his door. He pulled the door to reveal none other than Undyne, who still donned her armor. “Is the pasta ready?”

She had already let herself in, looking a little tired from her training, clearly still worn out from yet another day’s work. The knight soon followed where the scent was coming from, leading her to the kitchen.

“YOU CAME!” Papyrus exclaimed excitedly. So she saw his invitation. What a relief, he thought. With her around, he wouldn’t have to be alone to eat. He seemed very happy to see her, though, it wasn’t rare for Undyne to come over, so there was no reason to be hyped about it.

“Am I late?” she asked, settling down in her seat.

“NO, YOU’RE JUST IN TIME!” he exclaimed from the kitchen counter, hurrying to get the pasta over at the table where Undyne had sat. He gently placed it down with her fork, offering her a big smile. “HERE! TAKE A BITE!”

Undyne shut her eyes close, hoping for the best. His cooking were usually a disaster, but this time she had been proven wrong. “HOW IS IT?”

“Your pasta actually tastes good for once!” she laughs, feeling great. This one was the best one so far!

“IT DOES?” Papyrus said, “LET ME TRY THAT!”

Hurrying over to the utensils, the male grabbed a fork for himself, so he could taste his work. He twirled his fork into it, shoving it into his mouth, his face acquiring a few smudge from it in the process. His eyes lit up. “IT REALLY DOES!”

The tall woman smiled, sets her fork down, and started wiping off the red sauce that smudged his cheek. “DON’T GO PLACING YOUR FINGERS INTO OTHER PEOPLE’S FACES, UNDYNE!”

“WAIT, THERE’S A LITTLE SOMETHING ON YOUR FACE. I THINK YOU HAVE THE SAUCE ON YOU AS WELL!” he claimed. “ALLOW ME TO GET IT FOR YOU.”

He pressed the tips of his fingers on her lips, where the red stain had been. “You’re the one to talk.”

“BUT YOU DID IT FIRST, SO IT’S ONLY FAIR THAT I GOT BACK AT YOU AND RETALIATE.” Papyrus reasons, his hand still stuck by her chin. Undyne was looking into his eyes.

The two burst out in laughter. “Man, this is awkward!”


	2. CHEMICAL REACTIONS

**[   U N D E R S W A P   ]**

 

Undyne held the test tubes closer to her face for inspection, examining its contents. She watched as the substance bubbled but not enough to impress her. “I don’t get it. Why can’t I get a reaction?”

The genius Undyne has yet to find an answer for that.

“One, these are _a mess_. Two, you’ve mixed up some names here. How can you concentrate properly and find the chemicals needed in a disorganized list like this?” Papyrus concluded, who happened to be behind her, going over her research. “And lastly, you’re not doing it right. No wonder nothing happened.” He was skimming through her papers with a bored expression. He had an unlit cigar in between his teeth, and his hand tucked into his pocket. It was a good thing he wasn’t smoking. Undyne couldn’t stand its horrid stench that somehow sticks to her coat, or times when she inhales the toxic gas, burning her nose in the process.

He picked up a manga that was sprawled on the cabinet, spotting a few more along with it. “Are these your stuff? How unprofessional.”

“Don’t touch those.” the redhead said in a warning tone. He went through more of her belongings, despite her telling him not to. He lets himself in her small kitchen, finding emptied mugs of coffee. Undyne made extra sure to lock the doors. Then again, he’s _Papyrus_.

“Too much caffeine can be bad for you, you know.” he placed the papers down, taking out his lighter. Of course, she couldn’t let him smoke here, simply because most of the chemicals on the room were highly flammable.  _He_ , of all people, should know.

Just when he was about to light it, she grabbed it from in between his fingers. “And so is too much smoking. I can't have you going around polluting the lab.”

Papyrus’s brows shot up, quite surprised she had enough guts to take it from him. “It’s not like I’m not allowed to smoke here.”

The scientist puts his cigar where it was safe from her friend’s reach, returning to her station. “You’re not. You can have it back when you’re outside.”

Papyrus slides to her side, eyeing her as she poured in a bit more of the red liquid into the halfway filled beaker. He was peeking from over her shoulders, checking if what she did would do anything. It fizzled a bit, and the liquid turned into a brighter shade. The redhead was anticipating something extraordinary to happen. That’s when an idea struck him. “Let’s make a deal then. If I help you finish your little project, you’ll have to give me that back. It’s a win-win.”

“Let’s see you try then.” she steps aside to give way.

Cracking his knuckles, the man proceeded reading some of her notes. “Not to brag, but I just happen to be the former Royal Scientist here. All until I let you take over.”

“Alright, Mr. Smarty pants. How do  _you_  suggest I do it?” Undyne had crossed her arms over her chest, lending him some more space and access to the equipment before them.

Undyne was careful and complete with all sorts of instruments, Papyrus would give her that. He got a hold of one of the test tubes, taking a closer look. He then wrapped his fingers around one of the container, filling it up with extra care. The liquid started changing colors. A  _reaction_. Undyne expected nothing less from a former Royal Scientist as him. “Like this. Now you try,”

Both of his hands returned into his pockets, and steps back. When it was her turn to, the chemicals were as is. “It’s not working.”

“If you want it to actually work, you have to put more spirit into it. Put a little faith in yourself.” he encouraged. “You can do it.”

“I’m  _trying_.”

“Make sure you have the measurements right.”

“They have absolutely no chemistry between them! See? Not even a single reaction!” the scientist said. She blushed when his enormous hands was over hers, holding the receptacle in place. Undyne squeaked when she turned, flustered that their nose were centimeters away from touching. Her cheeks burned a bright red, and Papyrus smirked.

“BUT YOU TWO SURE HAVE!” Sans blurted and bursts through the door, making Undyne lose her grip on the vial.

“S-Sans! What are you doing here?”

“Weren’t you supposed to be at Alphy’s?” Papyrus asked. “You told me you had training today.”

“PAPYRUS PROMISED ME HE’D TAKE ME TO THE PLACE I LIKE.” the small, hyperactive ball of energy asked. “WAS I INTERRUPTING SOMETHING?”

“No, no. Undyne here was just about to kiss me.” Papyrus leaned in, pressing his forehead to hers. “Right, Undyne?”

“YOU WERE?” the boy blushes at the sight. He was too young to even look!

“Do you want to stay and see us _kiss_?” Papyrus slyly looped his arms around her waist, earning a blush from the scientist.

“I THINK I HEAR ALPHYS CALLING FOR ME. SHE SAYS I’M LATE FOR TRAINING. YOU TWO HAVE FUN KISSING!”

“Now, about my cigarette.”

Undyne wished she locked the lab earlier.

**Notes for the Chapter:**

> Sorry for the lack of detail or any actual science action! I'm not into science or am I qualified to say anything here is credible (/ω＼)


	3. DESCENT TO MADNESS

**[   S W A P F E L L   ]**

 

A bloodcurdling scream erupted from the labyrinth and mazes of doors, some of which Papyrus remembered. It might not be his business to meddle with the whole test going on, but he wasn’t going to lie around and miss out. Funny thing was that he wasn’t even supposed to be in the lab.

The only plausible reason why he was around was to check on the Royal scientist and how the subjects were doing.

On the way there, the male arrives to see trails of thick liquid leading to the metal door he was most familiar with. Scratches decorated the bottom of the threshold, and the very door itself was about to give out at any second—that if he even so much as kicked it open, the entire thing would have crashed down on the floor.

Careful not to break the metal, he pushes it gently, making this small squeaking noise. He wasn’t surprised to see who was inside.

Coat soaked in crimson, innards clinging onto her gloves, Undyne didn’t mind the putrid smell emanating from the corpse she was currently dissecting.

Blood seeped between the tiles of the floor, filling in the empty spots with the murderous color.

Upon entering, Papyrus’s nose automatically scrunched up. It wasn’t unusual for him to walk in on one of her sessions and find the mad scientist performing such disturbing operations.

Papyrus never found it in himself to lecture her about cleaning the lab and how she should dispose the rotting flesh before the flies start to come in. He couldn’t bring himself to—not when she had a hold of her tools. He didn’t want to get mangled, should he ever startle or provoke her.

He could never truly understand what it means or why she does these horrendous experiments. Maybe it was in her nature to be this way. Papyrus never understood the point in doing these kinds of things, and it’s worrying him to an extent where he actually considered approaching her. Of course, he values his life, so that would be for later.

It wasn’t like  _he_ was any different.


	4. PEACEFUL PARTINGS

**[   U N D E R T A L E   ]**

The moment Undyne laid eyes on the human, she knew right from the very start that the child was not to be trusted. Behind every soul lost was that  _human_. The king was right about humans. She should’ve listened.

And now, the child will pay for it. They will pay for what they have done.

Her skeleton friend never missed a single meeting. He would come whenever she called, that he would answer within the first two rings. When he didn’t pick it up, she knew what was up, and she knew it had something to do with the human. She soon realized that she would never get to see him again. The Papyrus she trained everyday was gone.

This wasn’t supposed to happen. Then again, Papyrus was too sweet for this world.

What has gotten into the human? Why would they kill him? He never did anything wrong.

Why?

Of all the monsters they could kill, why  _him?_

He’s her  _friend_.

He may be gone but there’s no point in using past tenses because he still is her friend, and forever will be. And there was no way she would let the human pass. She won’t give them a chance to destroy their world.

Does the human think they could get away with every single murder? Well, that’s where the child was wrong.

And she was not about to let it slide. Especially with what they’ve done to him.

How sick of a person they were, to kill off such a sweet monster.

Papyrus was too kind, too compassionate to consider hurting them. Had they no mercy?

Watching the human go further made her want to drive her spear through their tiny body and hit them where it hurts.

Frisk’s smile  _infuriated_  her. The grip on her weapon tightened each second. Standing before her, the child grinned, zeroing in on the helpless Monster Kid.

Undyne was not about to let them take away another soul. At the last minute, she shielded the boy with her own body.

The hit she took for Monster Kid did her enough damage. A  _single_  hit. How pathetic was that?

Undyne the Undying, losing to the human? An experienced warrior against a child?

Somehow, with those petty hits, she was already fading. Pain was clear on her face, struggling with the wound she’d sustained. Undyne cursed under her breath. How could she avenge Papyrus’s death now? How can she save lives when she herself was on the brink of losing the fight?

It would forever haunt her why she wasn’t able to protect the people close to her, who were part of her life. Some may think it wasn’t her fault for not stopping the human sooner, but had she known this would happen, she wouldn’t have let things get out of hand. The captain let out a low sigh, as she can no longer afford to waste any breath. She was slowly losing her strength all at once. So this was what it felt like for her skeleton friend to turn into dust. He must’ve been in so much pain; scared to face the human, forced to threaten them even when he didn’t mean it.

Her body may feel like it’s splitting apart, like she would scatter into the wind in a million pieces, but there was something that refused to let her succumb to her wound, to her tragic doom. This wasn’t how she wanted things to end. Deep inside, something was burning, screaming at her, refusing to let her die.

If she allows the human through, or if she was defeated, they would not only destroy the monsters, but the humans as well.

As if Undyne the Undying would let that happen!

The dying captain transformed into a new form, making her invincible, but she wasn’t sure for how long she’d last. That punk better be ready for a full beating!

If Papyrus were here, he’d convince her to befriend them instead of resorting to violence. There was no use stopping her now.

Papyrus was gone.

_It was now or never._

The lady knight went on in full speed.

Charging right at the child, she swung her spear. She was giving it her all.

With her every attack, the human staggers back. She couldn’t count how many times they’d come back up after grazing the human. Why weren’t they taking any effect? And how could Frisk possibly dodge her attacks in time to reciprocate her own?

The warrior couldn’t land a decent blow that could’ve knocked out the murderer.

For the first time, Undyne was truly afraid. She dread for the outcome, that if she doesn’t defeat the human, they would hurt more people that she cared about. Of course, she doesn’t let it show. The world might not be watching, but someone is.

One more hit, and it would all be over for her.

The amount of power she had acquired wasn’t enough.

Frisk lashed at her.

She could see the look on the human’s face, the corner of their lips rose to a smirk, as if they were satisfied with her defeat. “If you think I’m gonna give up hope, you’re wrong.”

The indifferent human didn’t respond. “I’ve got my friends behind me!”

“Alphys told me she would watch me fight you!” she grinned, her body shaking as it can no longer exist. She shouldn’t worry about that. Alphys would take care of the rest. “And if anything went wrong, she would evacuate everyone. By now, she’s called Asgore and told him to absorb the six souls.”

“And with that power,” her legs were giving away. “This world will live on.”

The mighty Undyne was slowly losing all the feeling and control over her body. She was actually dying.

But she won’t be alone.

Now, Papyrus won’t be the only one to have his dust all over across the Underground. She would join her fallen comrade and be at peace. She had done her part. This was the end.

**Notes for the Chapter:**

> The title is ironic because none of their deaths were peaceful, I think? Also, this is sort of written in her thoughts which explains why there aren’t much spoken between them. I wanted to mix two timelines and kinda came up with this idea instead! Hope that cleared things up!


	5. TROUBLE IS A FRIEND

**[   U N D E R S W A P  ]**

 

“Undyne, the queen’s going to come over in a minute. She would like to talk about some private matter, I guess.” Papyrus lazily announced, dragging his way to the lab, his hands in his pockets.

Turning away from the papers she was working on, she finds her friend by the door. Hearing this, the scientist dropped the pen she had in hand. “She is?”

“And she’s on her way here.” Papyrus informed her. “Queen Toriel wanted to see the project coming together and check how you’re doing.”

Undyne hurried to clear her desk. “But the place is a mess!”

Papyrus gave the room a quick sweep. It wasn’t _that_ bad. Papers clutter the floor and more paper just about everywhere. The male was no stranger to this. He had worse. “That shouldn’t be a problem. I’m sure the Queen wouldn’t mind.”

“To you it’s not a problem, but we’re talking about the _Queen_ here!” the current scientist lifted the stack files and folders, putting it right next to the other ones she placed earlier. What would the queen do when she walks in and sees the room? That would be too embarrassing, and Undyne definitely did not want that to happen!

Papyrus, having recently retired, left her a huge mess in the lab. Her papers were placed in places where they shouldn’t be, and that’s because the scientist before her didn’t bother cleaning up, leaving it all for her to handle. He was the reason why she was in this situation in the first place! “So what do you want me to do?”

“ _Anything_. Just keep Her Majesty distracted for as long as you can!” she instructed him, frantically hiding and shoving the trash aside.

“Alright, if it really bothers you that much,” the former scientist—who was finished with his cigarette, dumping it in the trash bin—suggested the most wonderful idea he had yet. “You fix things up while I’ll go and entertain Her Highness.”

Before she could even say anything, Papyrus was gone in an instant, giving her extra time to start tidying her work space. She better make the most of it.

There wasn’t any problem there. Undyne hates wasting time. She was practically zooming from one corner to another, checking the cabinets if there were any misplaced items.

Nothing seemed to be in need of fixing, or adjusting. The scientist just had to put the other instruments and apparatuses back in their proper places. And clean them, if possible.

Collecting the flasks to place them beside the tube rack, one of the many glass container she was holding had slipped from her arm.

“No, no, no!” Undyne hurries over the shards of broken glass, helplessly watching as the contents form a puddle, seeping in between the floor tiles. The Queen would definitely not like this. Wasting and breaking these precious resource and equipment was the last thing she needed.

Panicked, the scientist tried to pick some up with her bare hands to hide any evidence—obviously it didn’t work or go the way she planned. Once she bent down to collect the scattered pieces, she yelped, pricking herself in the process. Small amounts of blood dripped down her fingers, and her breath was shaking. What should she do?

The noise apparently caught the Papyrus’s attention. “Is everything okay here, Undyne?”

Behind the male, the Queen appeared to be in shock herself. And her presence made Undyne feel uneasy, after the little accident. “What is this?”

“Q-Queen Toriel!” she immediately shot up and bowed. She hoped she could get her words right. Her tongue never cooperates with her and ends up stuttering out the words. Word formed in her head but she was in too much pressure to speak them out. “I can explain!”

Clearing his throat, Papyrus—who was by the door—spoke up instead. “Undyne here was cleaning up after me. The tube slipped from my hand. My bad.”

“I see.” Toriel nodded in understanding, as if already expecting that it was the male’s fault. “We shall discuss the subject at a later time. And I expect your hand to recover by that time. Carry on then.” she headed towards the door, and just like that, disappeared from sight.

With a sigh of relief, the scientist spun on her heels to throw her arms around him. “Thanks for covering me.”

“No biggie.” he said, chuckling. He patted her in the back, and smirked. “You owe me one.”

Undyne shook her head in response.

“But first, we need to do something about your hand.” the male reminded and gestured to her injury.

“Right.” Undyne said, pulling away from him with an embarrassed smile.


End file.
